Charge compensation and enhanced photoluminescence of Sr ₂SiO₄:Eu³⁺, Li⁺ phosphor

A Eu³⁺ activated strontium silicate phosphor was synthesized by solid-state reaction and Li⁺ ion was added to balance the charge valence. X-ray powder diffraction analysis confirmed the formation of pure Sr₂SiO₄ phase without second phase or phases of starting materials irrespective of the adding amount of Li⁺. Scanning electron microscopy showed large particle size and necking shape were obtained as the concentrations of Li⁺ ions increase. In the PL studies, the excitation spectrum of Sr₂SiO₄:Eu³⁺,Li ⁺ phosphors exhibited a broad band in the UV region centered at about 270 nm attributed to charge transfer state (CTS) band. As the Li⁺ ion concentration increased, the photoluminescence intensity of the red emission at 617 nm of Eu³⁺ ions was enhanced. The results showed that Li ⁺ ion is a effective charge compensators used in Sr ₂SiO₄:Eu³⁺ phosphor.